OpenGL/sdl 2d texture

Im just starting out with opengl. Im focusing on 2d programming first.

My question is what is the difference between displaying/setting up 2d textures and 3d textures? Ive been looking for a tutorial on 2d opengl/sdl image displaying but after many hours of frustration I only found 3d texture examples. Im not sure whether I should try and modify the examples so that I could use it for my 2d game.